Session Tracking using URL Rewriting : Love Java Bytes

Project View :

Create login table and insert data into login table using insert command and here we are using Oracle10g database(you can also use other database)

 create table login ( id number,  
 uname varchar2(20),  
 upass varchar2(20)  
 );

 insert into login values (1,'him','him123');
 insert into login values (2,'bon','bon123');
 insert into login values (3,'jim','jim123');
 commit;

URL Rewriting Example:
In this example we are searching all users in login table using username or password and if you want to see all users present in login table just make a click on submit button.

Then we are performing Update and delete operation on row data using URL Rewriting.

Every row has a unique id created into database table and we append that id into URL of Servlet on which we are performing the task.

      <a href=UpdateServlet?id="+i+">Update</a>  
      <a href=DeleteServlet?id="+i+">Delete</a>

To get the Parameter value of Parameter Name(id) we use getParameter() method. we can send multiple Parameter values append with multiple Parameter names using Ampersand(&) to separate them.

<a href=Servlet?PN1=PV1&PN2=PV2&PN3=PV3>LinkName</a>

index.jsp
click on Search Link.

 <html>  
   <head>  
     <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">  
     <title></title>  
   </head>  
   <body>  
     <h1><a href="Search_Servlet">Search</a></h1>  
   </body>  
 </html>

web.xml

 <?xml version="1.0" encoding="UTF-8"?>  
 <web-app version="2.5" xmlns="http://java.sun.com/xml/ns/javaee" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd">  
   <servlet>  
     <servlet-name>Search_Servlet</servlet-name>  
     <servlet-class>Search_Servlet</servlet-class>  
   </servlet>  
   <servlet>  
     <servlet-name>UpdateServlet</servlet-name>  
     <servlet-class>UpdateServlet</servlet-class>  
   </servlet>  
   <servlet>  
     <servlet-name>DeleteServlet</servlet-name>  
     <servlet-class>DeleteServlet</servlet-class>  
   </servlet>  
   <servlet-mapping>  
     <servlet-name>Search_Servlet</servlet-name>  
     <url-pattern>/Search_Servlet</url-pattern>  
   </servlet-mapping>  
   <servlet-mapping>  
     <servlet-name>UpdateServlet</servlet-name>  
     <url-pattern>/UpdateServlet</url-pattern>  
   </servlet-mapping>  
   <servlet-mapping>  
     <servlet-name>DeleteServlet</servlet-name>  
     <url-pattern>/DeleteServlet</url-pattern>  
   </servlet-mapping>  
   <session-config>  
     <session-timeout>  
       30  
     </session-timeout>  
   </session-config>  
   <welcome-file-list>  
     <welcome-file>index.jsp</welcome-file>  
   </welcome-file-list>  
 </web-app>

MyDAO.java

 import java.sql.*;  
 public class MyDAO {  
   public static Statement getSt()  
   {  
     Statement st=null;  
     try  
     {  
       Class.forName("oracle.jdbc.driver.OracleDriver");  
       Connection con=DriverManager.getConnection("jdbc:oracle:thin:@localhost:1521:xe","hr","hr");  
       st=con.createStatement();  
     }  
     catch(Exception e)  
     {  
       System.out.println(e);  
     }  
     return st;  
   }  
 }

Search_Servlet.java

 import java.io.IOException;  
 import java.io.PrintWriter;  
 import javax.servlet.ServletException;  
 import javax.servlet.http.HttpServlet;  
 import javax.servlet.http.HttpServletRequest;  
 import javax.servlet.http.HttpServletResponse;  
 import java.sql.*;  
 public class Search_Servlet extends HttpServlet {  
   protected void doGet(HttpServletRequest request, HttpServletResponse response)  
   throws ServletException, IOException {  
     searchForm(request,response);  
     }   
   protected void doPost(HttpServletRequest request, HttpServletResponse response)  
   throws ServletException, IOException {  
     response.setContentType("text/html");  
     PrintWriter out=response.getWriter();  
     searchForm(request, response);  
     out.println("<center>");  
     String s1=request.getParameter("t1");  
     try  
     {  
      Statement st=MyDAO.getSt();  
      ResultSet rs=st.executeQuery("select * from login where uname like '%"+s1+"%' or upass like '%"+s1+"%'");  
      out.println("<table border=1>");  
      while(rs.next())  
      {  
        int i=rs.getInt(1);  
        out.println("<tr>");  
        out.println("<td>"+rs.getString(2)+"</td>");  
        out.println("<td>"+rs.getString(3)+"</td>");  
        out.println("<td><a href=UpdateServlet?id="+i+">Update</a></td>");  
        out.println("<td><a href=DeleteServlet?id="+i+">Delete</a></td>");  
        out.println("</tr>");  
      }  
      out.println("</table>");  
     }  
     catch(Exception e)  
     {  
       out.println(e);  
     }  
   }  
   private void searchForm(HttpServletRequest request, HttpServletResponse response) throws ServletException,IOException {  
     response.setContentType("text/html");  
     PrintWriter out=response.getWriter();  
     out.println("<html><body>");  
     out.println("<form method=post>");  
     out.println("<center>");  
     out.println("<h1>Make Your Search</h1>");  
     out.println("<br>");  
     out.println("<input type=text name=t1>");  
     out.println("<br>");  
     out.println("<input type=submit value=Submit>");  
     out.println("</center>");  
     out.println("</form>");  
     out.println("</body></html>");  
   }  
 }

UpdateServlet.java

 import java.io.IOException;  
 import java.io.PrintWriter;  
 import javax.servlet.ServletException;  
 import javax.servlet.http.HttpServlet;  
 import javax.servlet.http.HttpServletRequest;  
 import javax.servlet.http.HttpServletResponse;  
 import java.sql.*;  
 public class UpdateServlet extends HttpServlet {  
   String uname,upass;  
   Statement st;  
   static String ii;  
   protected void doGet(HttpServletRequest request, HttpServletResponse response)  
   throws ServletException, IOException {  
     response.setContentType("text/html");  
     PrintWriter out=response.getWriter();  
     try  
     {  
       ii=request.getParameter("id");  
       st=MyDAO.getSt();  
       ResultSet i=st.executeQuery("select * from login where id='"+ii+"'");  
       if(i.next())  
       {  
         uname=i.getString(2);  
         upass=i.getString(3);  
       }  
       out.println("<html><body>");  
       out.println("<form method=post>");  
       out.println("<center>");  
       out.println("<h1>Update Form</h1>");  
       out.println("<table>");  
       out.println("<tr>");  
       out.println("<td>");  
       out.println("User Name : ");  
       out.println("</td>");  
       out.println("<td>");  
       out.println("<input type=text name=t1 value="+uname+">");  
       out.println("</td>");  
       out.println("</tr>");  
       out.println("<tr>");  
       out.println("<td>");  
       out.println("Password : ");  
       out.println("</td>");  
       out.println("<td>");  
       out.println("<input type=text name=t2 value="+upass+">");  
       out.println("</td>");  
       out.println("</tr>");  
       out.println("<tr>");  
       out.println("<td>");  
       out.println("<input type=submit value=Submit>");  
       out.println("</td>");  
       out.println("</tr>");  
       out.println("</table>");  
       out.println("</center>");  
       out.println("</form>");  
       out.println("</body></html>");  
     }  
     catch(Exception e){out.println(e);}  
   }  
 protected void doPost(HttpServletRequest request, HttpServletResponse response)  
   throws ServletException, IOException {  
     response.setContentType("text/html");  
     PrintWriter out=response.getWriter();  
     String s1=request.getParameter("t1");  
     String s2=request.getParameter("t2");  
     out.println(s1+" "+s2+" "+ii);  
     try  
     {  
      Statement st=MyDAO.getSt();  
      int i=st.executeUpdate("update login set uname='"+s1+"',upass='"+s2+"' where id='"+ii+"'");  
      if(i!=0)  
      {  
        out.println("Updated Successfully");  
      }  
     }  
     catch(Exception e){out.println(e);}  
   }  
 }

DeleteServlet.java

 import java.io.IOException;  
 import java.io.PrintWriter;  
 import javax.servlet.ServletException;  
 import javax.servlet.http.HttpServlet;  
 import javax.servlet.http.HttpServletRequest;  
 import javax.servlet.http.HttpServletResponse;  
 import java.sql.*;  
 public class DeleteServlet extends HttpServlet {  
   protected void doGet(HttpServletRequest request, HttpServletResponse response)  
   throws ServletException, IOException {  
     response.setContentType("text/html");  
     PrintWriter out=response.getWriter();  
     try  
     {  
       String i=request.getParameter("id");  
       Statement st=MyDAO.getSt();  
       int j=st.executeUpdate("delete from login where id='"+i+"'");  
       out.println("<html><body><h1>");  
       out.println(j+" record(s) deleted");  
       out.println("</h1></body></html>");  
     }  
     catch(Exception e){out.println(e);}  
   }   
 }